Dformation Characteristic Of Longmenshan Anxian-Guanxian Fault Zone—the Research Of Wenchuan Earthquake Fault Zone Scientific Drilling Project (WFSD-3P)Cores And Logging

The longmen mountain is composed of three major thrust faults from west to east,which includes Wenchuan-Maoxian fault(Longmen mountainfront fault),Yngxiu-Beichuan fault(The central fault of Longmen mountain),and Anxian-Guanxian fault(Longmen mountainbehind the fault)。This paper focus on the research of the Parahole cores of Guanxian-Anxian fault zone,Wenchuan Eearthquake Fault Zone Scientific Drlling Project No.3 Pole (WFSD-3P)。We find from study that four faults occer in the cores of WFSD-3P, FZ451、FZ464、FZ490、FZ507 respectively (the numbers represent their depths), FZ507 of which are the boundary between Triassic and Jurassic and the major sliding surface witnessed by logging data and fresh gouges。The dip angle of FZ507 is 46°and the tendency is NW by measuring。The pure thrust is the character of this fault zone revealed from mirror tectonic and scratching in cores, which is accordance with the shows of surface rupture。Multiple stacking is the mainly reason of formation longmen mountain.The thickness of the gouge in four major fault zones is about 19 meters. As Taiwan chi-chi earthquake revealed,0.3 millimeters to 2 centimeters thickness gouge formations from once earthquake, which shows that there were multiple activities of earthquake once, and they maybe Concealed faults。According to the lithology column of the WFSD-3P, it Shows clear asymmetry。Detailed study was taken shows that the character is related to the kinematic features。Combined with the anomaly of logging,The position of major slide-plane can be decided in the 507m,and Thear stress that aroused the Wenchuan earthquake can be gained from calculating. We have learned further the microtectonic character of brokenrock by microscopic observation rock chip,and analysed them.